Semiconductor chip package having ground and power regions and manufacturing methods thereof

ABSTRACT

A semiconductor package and related methods are described. In one embodiment the semiconductor package includes a die pad, a plurality of leads, a semiconductor chip, and a package body. The die pad includes a first part that includes a lower surface and a first peripheral edge region comprising a ground region. The die pad further includes a second part that is spaced apart from the first part and that includes a lower surface and a second peripheral edge region comprising a power region. The plurality of leads is disposed around the die pad. The semiconductor chip is disposed on the die pad and is electrically coupled to the ground region, the power region, and the plurality of leads. The package body is formed over the semiconductor chip and the plurality of leads.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of the following commonly owned U.S. provisional patent application, which is incorporated herein by reference in its entirety: U.S. Provisional Patent Application No. 61/036,470, Attorney Docket No. ASEG-001/00US, entitled “Chip Package Structure and Manufacturing Methods Thereof,” filed on Mar. 14, 2008.

FIELD OF THE INVENTION

The present invention relates generally to semiconductor chip packages. More particularly, this invention relates to a semiconductor chip package having ground and power regions and manufacturing methods thereof.

BACKGROUND OF THE INVENTION

Semiconductor chips have become progressively more complex, driven in large part by the need for increasing processing power in a smaller chip size. In response, packaging technologies have evolved, for example, to enable an increased lead density, which can reduce the footprint area of a package mounted on a printed circuit board (PCB). Some packaging technologies, such as Quad Flat No Lead (QFN), may enable this increased lead density by providing inner and outer rows of leads connected to a disposable portion of a leadframe. However, manufacturing processes for such leadframes may not be scalable beyond two rows of leads. As lead density requirements further increase, it may be desirable to use packaging technologies that are more scalable in terms of lead density.

As semiconductor chips become more complex, the number of bonding pads on a chip may increase to enable additional electrical connections. Between 25 and 30 percent of these bonding pads can be used for ground and power connections of the chip. The ground connections can be to an upper surface of a ground ring that extends completely around the chip. Similarly, the power connections can be to an upper surface of a power ring that extends completely around the ground ring. Leads can then substantially surround the power ring. To prevent short-circuits, the ground ring, the power ring, and the leads are all typically physically separated from each other by a minimum separation distance. The combination of the ground ring, the power ring, and the separation distance between the ground ring and the power ring can occupy, and thus exclude leads from, a significant percentage of the footprint area of a package. It may be desirable to reduce package size by reducing the area requirements of the ground and power connections of the chip.

Moreover, it may be desirable to further reduce package size in additional ways, such as by reducing package height. At the same time, it may be desirable to maintain sufficient mold locking of leads to a package body. In addition, it may be desirable to facilitate surface mounting of the package to a PCB. For example, it may be difficult to determine how to properly orient the package during surface mounting to the PCB. It may also be desirable to increase the reliability of surface mounting of the package to the PCB. For example, stress due to differential thermal expansion between the leads and the package body may be concentrated at the corners of the package, which can lead to cracking of solder connections to the PCB near the corners of the package, and thus to a decrease in the reliability of surface mounting. It may also be desirable to formulate a packaging process designed to meet these objectives. Current packaging solutions can meet some of these objectives but may not be able to meet most, or all, of these objectives.

It is against this background that a need arose to develop the chip package and associated manufacturing methods described herein.

SUMMARY OF THE INVENTION

In one innovative aspect, the invention relates to a semiconductor package. In one embodiment, the semiconductor package includes a die pad, a plurality of leads, a semiconductor chip, and a package body. The die pad includes: (1) a first part that includes a lower surface and a first peripheral edge region comprising a ground region; and (2) a second part that is spaced apart from the first part and that includes a lower surface and a second peripheral edge region comprising a power region. The plurality of leads is disposed around the die pad. The semiconductor chip is disposed on the die pad and is electrically coupled to the ground region, the power region, and the plurality of leads. The package body is formed over the semiconductor chip and the plurality of leads.

In another innovative aspect, the invention relates to a semiconductor package. In one embodiment, the semiconductor package includes a die pad, a plurality of leads, a power segment, a semiconductor chip, and a package body. The die pad includes: (1) a base including an upper surface and a lower surface; (2) a protrusion disposed adjacent to the base, wherein the protrusion includes an upper surface and a lower surface, and wherein at least a portion of the protrusion is a ground region; and (3) a first side surface extending between the upper surface of the protrusion and the lower surface of the protrusion, the first side surface including a first peak. The plurality of leads is disposed around the die pad, each including a lower surface with a first surface area. At least one of the plurality of leads includes a second side surface including a second peak. The power segment is disposed adjacent to the protrusion, and includes a lower surface with a second surface area that is at least three times greater than an average of the first surface areas of the plurality of leads. The semiconductor chip is disposed on the upper surface of the base and is electrically coupled to the ground region, the power segment, and the plurality of leads. The package body is formed over the semiconductor chip and the plurality of leads so that the package body substantially covers the upper surface of the base, at least a portion of the first side surface above the first peak, and at least a portion of the second side surface above the second peak. The package body is also formed over the semiconductor chip and the plurality of leads so that at least a portion of the first side surface below the first peak and at least a portion of the second side surface below the second peak protrude from a lower surface of the package body.

In a further innovative aspect, the invention relates to a semiconductor package. In one embodiment, the semiconductor package includes a die pad, a plurality of leads, a semiconductor chip, and a package body. The die pad includes: (1) a base including an upper surface and a lower surface; (2) a protrusion disposed adjacent to the base, wherein the protrusion includes an upper surface and a lower surface with a first surface area, and wherein at least a portion of the protrusion is a ground segment; and (3) a first side surface extending between the upper surface of the protrusion and the lower surface of the protrusion, the first side surface including a first peak. The plurality of leads is disposed around the die pad, each including a lower surface with a second surface area, where the first surface area is at least three times greater than an average of the second surface areas of the plurality of leads. At least one of the plurality of leads includes a second side surface including a second peak. The semiconductor chip is disposed on the upper surface of the base and is electrically coupled to the ground segment and the plurality of leads. The package body is formed over the semiconductor chip and the plurality of leads so that the package body substantially covers the upper surface of the base, at least a portion of the first side surface above the first peak, and at least a portion of the second side surface above the second peak. The package body is also formed over the semiconductor chip and the plurality of leads so that at least a portion of the first side surface below the first peak and at least a portion of the second side surface below the second peak protrude from a lower surface of the package body.

In a further innovative aspect, the invention relates to a method of making a semiconductor package. In one embodiment, the method includes providing a metal carrier plate including: (1) a lower surface; (2) an upper surface including a die receiving area; (3) a plurality of peripheral bulges, each being disposed around the die receiving area and having an upper surface; (4) a first metal coating formed on the upper surfaces of the plurality of peripheral bulges; and (5) a second metal coating formed on the lower surface of the metal carrier plate below the plurality of peripheral bulges, a first part of the die receiving area, and a second part of the die receiving area. The method further includes attaching a semiconductor chip to the die receiving area, electrically coupling the semiconductor chip to the plurality of peripheral bulges, and forming a package body over the semiconductor chip and the plurality of peripheral bulges. The method further includes etching areas on the lower surface of the metal carrier plate without the second metal coating formed thereon such that: (1) the plurality of peripheral bulges, the first part of the die receiving area, and the second part of the die receiving area are separated from one another so as to form a plurality of leads, a first part of a die pad, and a second part of the die pad that is spaced apart from the first part; (2) each of the plurality of leads includes a sloped etched area disposed adjacent to a lower surface of the each of the plurality of leads; (3) each part of the die pad includes a sloped etched area disposed adjacent to a lower surface of the each part; and (4) the sloped etched areas of the first part and the second part of the die pad and of the plurality of leads at least partially extend outwardly from a lower surface of the package body.

Other aspects and embodiments of the invention are also contemplated. The foregoing summary and the following detailed description are not meant to restrict the invention to any particular embodiment but are merely meant to describe some embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the nature and objects of some embodiments of the invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates a cross-sectional view of a semiconductor package, in accordance with one embodiment of the present invention;

FIG. 2 illustrates a cross-sectional, enlarged view of a die pad, in accordance with one embodiment of the present invention;

FIG. 3 illustrates a cross-sectional, enlarged view of a lead, in accordance with one embodiment of the present invention;

FIG. 4 illustrates a top view of a portion of a metal carrier plate, in accordance with one embodiment of the present invention;

FIG. 5 illustrates processing operations for making a metal carrier plate, in accordance with one embodiment of the present invention;

FIG. 6 illustrates processing operations for making a semiconductor package, in accordance with one embodiment of the present invention;

FIG. 7 illustrates processing operations for making a semiconductor package including multiple stacked dies or chips, in accordance with one embodiment of the present invention;

FIG. 8 illustrates processing operations for making a semiconductor package and surface mounting the semiconductor package, in accordance with one embodiment of the present invention;

FIG. 9 illustrates processing operations for making a semiconductor package and surface mounting the semiconductor package, in accordance with another embodiment of the present invention;

FIG. 10 illustrates a top view of a portion of a metal carrier plate including a marker bulge and enlarged peripheral bulges, in accordance with one embodiment of the present invention;

FIG. 11 illustrates a cross-sectional view of a semiconductor package, in accordance with the embodiment of FIG. 10;

FIG. 12 illustrates a top view of a portion of a metal carrier plate including a die receiving area including a peripheral edge region, in accordance with one embodiment of the present invention;

FIG. 13 illustrates a bottom view of the portion of the metal carrier plate of FIG. 12, in accordance with one embodiment of the present invention;

FIG. 14 illustrates processing operations for making a semiconductor package including a ground region, in accordance with one embodiment of the present invention;

FIG. 15 illustrates a top view of a portion of a metal carrier plate including enlarged peripheral bulges and a die receiving area including a peripheral edge region, in accordance with one embodiment of the present invention;

FIG. 16 illustrates a bottom view of the portion of the metal carrier plate of FIG. 15, in accordance with one embodiment of the present invention;

FIG. 17 illustrates processing operations for making a semiconductor package including a ground region and a power region, in accordance with one embodiment of the present invention;

FIG. 18 illustrates a top view of a portion of a metal carrier plate including parts of a die receiving area including multiple parts, in accordance with one embodiment of the present invention;

FIG. 19 illustrates a bottom view of the portion of the metal carrier plate of FIG. 18, in accordance with one embodiment of the present invention; and

FIG. 20 illustrates processing operations for making a semiconductor package including a die pad with separated parts, in accordance with one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates a cross-sectional view of a semiconductor package 100, in accordance with one embodiment of the present invention. The package 100 includes a die pad 101 with a peripheral edge region 114 that defines a cavity 111 with a cavity bottom 112. The peripheral edge region 114 may completely surround the cavity 111, but also can partially surround the cavity 111 for certain implementations. The cavity bottom 112 includes a central portion 112 a. The cavity bottom 112 may also include a recess 112 b around the central portion 112 a. The central portion 112 a may be approximately centrally located within the cavity bottom 112, but need not be if, for example, the recess 112 b is of non-uniform width. The recess 112 b may completely surround the central portion 112 a, but also can partially surround the central portion 112 a for certain implementations. A chip 102 is attached to the cavity bottom 112 by an adhesive layer (not shown). The adhesive layer may be a conductive or a non-conductive adhesive material, such as non-conductive epoxy. In the illustrated embodiment, the chip 102 is attached to the central portion 112 a. Bonding pads 106 on the active surface of the chip 102 are electrically coupled to leads 171 through bonding wires 104, and may also be electrically coupled to at least part of the peripheral edge region 114 through bonding wires 104. The leads 171 are disposed around the die pad 102, and may completely or partially surround the die pad 101.

FIG. 2 illustrates a cross-sectional, enlarged view of the die pad 101, in accordance with one embodiment of the present invention. The die pad 101 includes a side surface 208, which may completely or partially extend around a circumference of the die pad 101. In the illustrated embodiment, the side surface 208 includes an upper sloped portion 208 c disposed adjacent to an upper surface 151 of the peripheral edge region 114 and facing away from the cavity 111. The side surface 208 also includes a lower sloped portion 208 a disposed adjacent to the upper sloped portion 208 c and facing away from the cavity 111. The peripheral edge region 114 also includes an upper sloped portion 218 disposed adjacent to the upper surface 151 and facing toward the cavity 111. Sloped portions 208 a, 208 c, and 218 may be linear or curved, and are typically non-perpendicular to the upper surface 151 of the peripheral edge region 114. The side surface 208 also includes a peak 208 b.

FIG. 3 illustrates a cross-sectional, enlarged view of a lead 171, in accordance with one embodiment of the present invention. The lead 171 includes a side surface 308, which may completely or partially extend around a circumference of the lead 171. In the illustrated embodiment, the side surface 308 includes an upper sloped portion 308 c disposed adjacent to an upper surface 155 of the lead 171. The side surface 308 also includes a lower sloped portion 308 a disposed adjacent to a lower surface 157 of the lead 171. Sloped portions 308 a and 308 c may be linear or curved, and are typically non-perpendicular to the upper surface 155 and the lower surface 157 of the lead 171. The side surface 308 also includes a peak 308 b.

Referring back to FIG. 1 along with FIG. 2 and FIG. 3, a package body 108 is formed over the chip 102, the die pad 101, and the leads 171 so that the package body 108 substantially fills the cavity 111 and substantially covers the upper sloped portions 218 of the peripheral edge region 114. The package body 108 also substantially covers the upper sloped portions 208 c of the die pad 101, and the upper sloped portions 308 c of the leads 171. In this context, the term “substantially” indicates, in part, that the cavity 111 having the chip 102 disposed on the cavity bottom 112 is filled by the package body 108; the term also indicates that the package body 108 typically fills the cavity 111 to sufficiently minimize or reduce pockets of air and moisture, and covers the chip 102, the bonding wires 104, and the upper sloped portions 208 c, 218, and 308 c to provide sufficient protection from oxidation, moisture, and other environmental conditions to meet packaging application requirements. In the illustrated embodiment, the lower sloped portions 208 a of the die pad 101 and the lower sloped portions 308 a of the leads 171 at least partially extend outwardly from a lower surface 160 of the package body 108. Alternatively, either the lower sloped portions 208 a of the die pad 101 or the lower sloped portions 308 a of the leads 171 may at least partially extend outwardly from the lower surface 160 of the package body 108.

The sloping of the upper sloped portions 208 c, 218, and 308 c can significantly increase the area of contact, and thus the adhesion between the package body 108 and the die pad 101, and between the package body 108 and the leads 171. This can thereby enhance the mold locking of the die pad 101 and the leads 171 in the package body 108. This can also prolong the path and time for moisture diffusion into the package 100.

In the illustrated embodiment, the upper sloped portions 208 c and 308 c have substantially concave profiles. In this context, the term “substantially” is used to indicate that the upper sloped portions 208 c and 308 c are generally concave, i.e. rounded inwards toward the center of the die pad 101 and the leads 171, but that the upper sloped portions 208 c and 308 c may include surface non-uniformities or roughness in the form of small peaks, such as asperities, that may be rounded outwards from the center of the die pad 101 and the leads 171. For example, FIG. 3 shows that the upper sloped portion 308 c of the lead 171 has an overall shape that is generally rounded inward toward the center of the lead 171. At the same time, the upper sloped portion 308 c is roughly textured with numerous asperities. These asperities engage the package body 108 during molding and thereby enhance mold locking of the lead 171 in the package body 108. These asperities can be formed through precisely controlled etching or some other suitable process. Similarly, the lower sloped portions 208 a and 308 a may have substantially concave profiles. In this context, the term “substantially” is used to indicate that the lower sloped portions 208 a and 308 a are generally concave, i.e. rounded inwards toward the center of the die pad 101 and the leads 171. For example, FIG. 2 shows that the lower sloped portion 308 c of the lead 171 has an overall shape that is generally rounded inward toward the center of the lead 171. Similarly, the upper sloped portions 218 may have substantially concave profiles. In this context, the term “substantially” is used to indicate that the upper sloped portions 218 are generally concave, i.e. rounded inwards toward the center of the peripheral edge region 114. For example, FIG. 2 shows that the upper sloped portion 218 of the peripheral edge region 114 has an overall shape that is generally rounded inward toward the center of the peripheral edge region 114.

It will be understood that the die pad 101 may be alternatively described. For example, in FIG. 2, the die pad 101 includes a base 202 with an upper surface 212 and a lower surface 153. In one embodiment, a protrusion 213 with an upper surface 151 extends upwardly from the base 202 and is disposed adjacent to a peripheral edge of the base 202. A side surface 208 extends between the upper surface 151 of the protrusion 213 and the lower surface 153 of the base 202, and includes a peak 208 b. Alternatively, the protrusion 213 may be disposed adjacent to the base 202, so that the protrusion 213 also has a lower surface 253. The side surface 208 then extends between the upper surface 151 and the lower surface 253 of the protrusion 213, and includes the peak 208 b. A side surface 218 also extends between the upper surface 151 of the protrusion 213 and the upper surface 212 of the base 202.

In one embodiment, the upper surface 212 of the base 202 includes a central region 212 a on which the chip 102 is disposed. The upper surface 212 may also include a recess 212 b around the central region 212 a. The central region 212 a may be approximately centrally located within the upper surface 212, but need not be if, for example, the recess 212 b is of non-uniform width. The recess 212 b may completely surround the central region 212 a, but also can partially surround the central region 212 a for certain implementations.

It will also be understood that the package body 108 may be alternatively described. For example, in FIG. 1, FIG. 2, and FIG. 3, the package body 108 is formed over the chip 102, the die pad 101, and the leads 171 so that the package body 108 substantially covers the upper surface 212 of the base 202 and the side surface 218. The package body 108 also substantially covers at least a portion of the side surface 208 above the peak 208 b, and at least a portion of the side surface 308 above the peak 308 b. In this context, the term “substantially” indicates, in part, that the upper surface 212 of the base 202 having the chip 102 disposed thereon is covered by the package body 108; the term also indicates that the package body 108 typically covers the chip 102, the bonding wires 104, the upper surface 212 of the base 202, the side surface 218, the portion of the side surface 208 above the peak 208 b, and the portion of the side surface 308 above the peak 308 b to provide sufficient protection from oxidation, moisture, and other environmental conditions to meet packaging application requirements. At least a portion of the side surface 208 below the peak 208 b protrudes from the lower surface 160 of the package body 108. Similarly, at least a portion of the side surface 308 below the peak 308 b protrudes from the lower surface 160 of the package body 108.

The package 100 may further include a metal coating 116 disposed on the upper surface 151 of the peripheral edge region 114 as shown in FIG. 1, alternatively described as disposed on the upper surface 151 of the protrusion 213 as shown in FIG. 2. The package 100 may also include a metal coating 117 disposed on the lower surface 153 of the die pad 101 as shown in FIG. 1, alternatively described as disposed on the lower surface 153 of the base 202 as shown in FIG. 2. Alternatively, the metal coating 117 may be described as being disposed on both the lower surface 153 of the base 202 and the lower surface 253 of the protrusion 213, as shown in FIG. 2. The package 100 may also include a metal coating 126 disposed on the upper surfaces 155 of the leads 171 as shown in FIG. 1, and a metal coating 127 disposed on the lower surfaces 157 of the leads 171 as shown in FIG. 1. These metal coatings can be disposed using techniques such as electrolytic plating and electroless plating. It is desirable that these metal coatings adhere well to the surfaces of the die pad 101 and the leads 171, enable effective wire bonding with bonding wires 104, and protect the lower surfaces of the die pad 101 and the leads 171 from oxidation and other environmental conditions. With these goals in mind, the metal coatings can include a layer of nickel in contact with the surfaces 151 and 153 of the die pad 101 and the surfaces 155 and 157 of the leads 171, and a layer of gold or palladium covering the layer of nickel. Alternatively, the metal coatings may include a layer of an alloy of nickel and either one of, or both, gold and palladium.

Referring to FIG. 1 along with FIG. 2 and FIG. 3, a standoff distance 148 can refer to the distance that the lower sloped portions 208 a of the die pad 101 and/or the lower sloped portions 308 a of the leads 171 extend outwardly from the lower surface 160 of the package body 108, and, for certain implementations, can include or otherwise account for a thickness of the metal coatings 117 and 127. Alternatively, the standoff distance 148 can refer to the distance that the portion of the side surface 208 below the peak 208 b and/or the portion of the side surface 308 below the peak 308 b protrude from the lower surface 160 of the package body 108. The protrusion of the die pad 101 and/or the leads 171 from the lower surface 160 of the package body 108 can enhance the solderability of the die pad 101 and the leads 171 to a PCB by exposing additional area on the die pad 101 and or the leads 171 to which solder can attach. This can increase the reliability of surface mounting of the package 100 to the PCB. In one embodiment, the peak 208 b is disposed closer to the lower surface 153 of the base 202 than to the upper surface 151 of the protrusion 213, and the peaks 308 b are disposed closer to the lower surfaces 157 of the leads 171 than to the upper surfaces 155 of the leads 171.

For certain implementations, the standoff distance 148 is between about twenty and about fifty percent or between about twenty-five and about forty-five percent of a thickness 142 of the die pad 101 and/or at least one of the leads 171, although the standoff distance 148 is not constrained to this range and, for other implementations, may be between about five percent and about seventy-five percent of the thickness 142. The thickness 142 of the die pad 101 can be measured as the distance between the upper surface 151 of the peripheral edge region 114 and the lower surface 153 of the die pad 101. If metal coatings 116 and 117 are disposed on surfaces 151 and 153 of the die pad 101, as is typically the case, then the thickness 142 can be measured as the distance between the upper surface 150 of the metal coating 116 and the lower surface 152 of the metal coating 117. Similarly, for a lead 171, if metal coatings 126 and 127 are disposed on surfaces 155 and 157 of the lead 171, as is typically the case, then the thickness 142 can be measured as the distance between the upper surface 154 of the metal coating 126 and the lower surface 156 of the metal coating 127. As described herein, various distances can be measured relative to the surfaces of metal coatings 116, 117, 126, and 127. However, it will be understood that these distances can be similarly measured relative to the surfaces 151 and 153 of the die pad 101 or the surfaces 155 and 157 of the leads 171, if any or all of the metal coatings 116, 117, 126, and 127 are not present.

In one embodiment, the thickness 142 of the die pad 101 including metal coatings 116 and 117 is substantially equal to that of at least one lead 171 including metal coatings 126 and 127, and is about 0.125 millimeters. In this case, the standoff distance 148 by which the die pad 101 and the at least one lead 171 protrudes from the lower surface 160 of the package body 108 is between about 0.025 millimeters and about 0.0625 millimeters or between about 0.03 millimeters and about 0.05 millimeters. Also, the peak 208 b of the side surface 208 of the die pad 101 is substantially level with the peak 308 b of the side surface 308 of the at least one lead 171. In an alternative embodiment, the thickness 142 of the die pad 101 and or the at least one lead 171 may be above or below 0.125 millimeters.

As the standoff distance 148 becomes a larger percentage of the thickness 142 within the range of about twenty to about fifty percent, the reliability of mold locking of the die pad 101 and/or the leads 171 in the package body 108 typically tends to decrease, while the reliability of surface mounting of the package 100 on a PCB typically tends to increase. At the same time, the duration and cost of bottom side etching (see FIG. 6) typically increases. The choice of the standoff distance 148 as a percentage of the thickness 142 can be a tradeoff between these factors.

A mold cap 140 can refer to the distance between an upper surface 164 of the package body 108 and the upper surface 150 of the metal coating 116. Similarly, for a lead 171, the mold cap 140 can be measured as the distance between the upper surface 164 of the package body 108 and the upper surface 154 of the metal coating 126. The mold cap 140 is typically large enough so that the chip 102 and the bonding wires 104 are enclosed within the package body 108. In one embodiment, the mold cap 140 is between about 0.4 millimeters and about 1 millimeter, such as about 0.675 millimeters, although the mold cap 140 can be smaller so long as the chip 102 and the bonding wires 104 remain sufficiently enclosed within the package body 108. The inclusion of the cavity 111 in the die pad 101 can enable the chip 102 to be disposed on the central portion 112 a of the cavity bottom 112 as shown in FIG. 1. Alternatively, the chip 102 can be disposed on the central region 212 a of the upper surface 212 of the base 202 as shown in FIG. 2.

In FIG. 1 and FIG. 2, distance 206 measures a depth of the central portion 112 a (or central region 212 a) relative to the upper surface 150 of the metal coating 116. Distance 204 measures a depth of the recess 112 b (or recess 212 b) relative to the upper surface 150 of the metal coating 116. For certain implementations, the distance 206 is between about fifty-five and about eighty percent of the distance 204, although the distance 206 is not constrained to this range. In one embodiment, the distance 206 is about 0.065 millimeters and the distance 204 is about 0.095 millimeters. Both the distances 204 and 206 may vary above or below these values, so long as the distances 204 and 206 remain less than the thickness 142 of the die pad 101 by some margin, such as about 0.01 millimeters. Preferably, the central portion 112 a (or central region 212 a) and the recess 112 b (or recess 212 b) are the result of etching (see FIG. 5), rather than plating to build up the peripheral edge region 114 (or central protrusion 213). Plating may be both more costly and time consuming than the etching process subsequently described and shown in FIG. 5.

By disposing the chip 102 on the cavity bottom 112 (or upper surface 212 of the base 202), the top surface of the chip 102 is lower by the distance 206 relative to the upper surface 150 of the metal coating 116, and relative to the upper surfaces 154 of the metal coating 126 on each lead 171. As a result, the mold cap 140 can be reduced, which can make the package 100 thinner. In addition, the lower surface of the chip 102 is closer by distance 206 to the lower surface 152 of the metal coating 117. This can enhance heat dissipation from the chip 102 through the die pad 101.

Referring to FIG. 1 along with FIG. 2 and FIG. 3, a height difference 146 refers to the distance between a plane 166 through the highest point of the central portion 112 a (or central region 212 a) and the lower surface 160 of the package body 108. The lower surface 160 of the package body 108 typically corresponds, at least approximately, to the lower surface of the package body 108 within the recess 112 b (or recess 212 b). For certain implementations, the height difference 146 is between about 0.02 millimeters and about 0.04 millimeters, although the height difference 146 is not constrained to this range. For certain implementations, the upper surface 150 of the metal coating 116 can be disposed between about 0.05 millimeters and about 0.08 millimeters above the plane 166, but is not constrained to this range. Also, the peak 208 b of the side surface 208 of the die pad 101 and the peak 308 b of the side surface 308 of at least one lead 171 may be disposed below the plane 166. The height difference 146 and the positioning of the peaks 208 b and 308 b relative to the plane 166 can be controlled by etching, such as through a top side etching process (see FIG. 5).

Distance 144 refers to the minimum distance from side surface 162 of the package body 108 to side surfaces 308 of any of the leads 171. In the embodiment of FIG. 1, distance 144 is illustrated as the distance from the side surface 162 to the peak 308 b of the leftmost outer lead 171A. For certain implementations, the distance 144 is between about 0.1 millimeters and about 0.3 millimeters, although the distance 144 is not constrained to this range. The portion of the package body 108 to the left of leftmost outer lead 171A (and similarly to the right of rightmost outer lead 171B) can prevent peeling and detachment of the outer leads 171A and 171B during singulation (see FIG. 6) and during use of the package 100.

Lead spacing 145, also referred to as terminal pitch, refers to the distance between the centers of a pair of adjacent leads 171. For certain implementations, the lead spacing 145 is between about 0.35 and about 0.55 millimeters, although the lead spacing 145 is not constrained to this range. The lead spacing 145 can be controlled by etching, such as through a top side etching process (see FIG. 5).

In FIG. 3, a protective layer 310 is shown substantially covering the lower sloped portion 308 a of at least one of the plurality of leads 171. In this context, the term “substantially” indicates that the protective layer 310 typically covers the lower sloped portion 308 a of the at least one lead 171 to sufficiently protect the underlying metal from oxidation, moisture, and other environmental conditions to meet packaging application requirements. The package body substantially covers the upper sloped portion 308 c (or the portion of the side surface 308 above the peak 308 b), but does not entirely cover the lower sloped portion 308 a (or the portion of the side surface 308 below the peak 308 b), or at least does not cover that part of the lower sloped portion 308 a that extends outwardly from the lower surface 160 of the package body 108. As a result, the protective layer 310 is included in addition to the protective metal coating 127 (see FIG. 1) on the lower surface 157 of the lead 171 to prevent or reduce oxidation and corrosion of the underlying metal, which is typically copper or a copper alloy. A similar protective layer may be applied to the lower sloped portion 208 a of the die pad 101 (or the portion of the side surface 208 below the peak 208 b). In FIG. 2, a protective layer 210 is shown substantially covering the lower sloped portion 208 a of the die pad 101. The protective layer 210, along with the protective metal coating 117 (see FIG. 1) on the lower surface 153 of the die pad 101, sufficiently protects the underlying metal of the die pad 101 to meet packaging application requirements.

In one embodiment, the protective layers 210 and 310 can include a metal coating. The metal coating may include at least one of a layer of tin, a layer of nickel, and a layer of gold. Alternatively, the metal coating may include a layer of an alloy of two or more of these metals. The metal coating may be attached to the lower sloped portions 208 a and 308 a using immersion, electrolytic plating, electroless plating, or any other suitable process.

In another embodiment, the protective layers 210 and 310 can include a solder material. The solder material may include a solder paste. The solder paste may be selectively disposed on the lower sloped portions 208 a and 308 a, while the protective metal coatings 117 and 127 (without the solder paste) substantially cover the lower surface 153 of the die pad 101 and the lower surface 157 of at least one lead 171. In this context, the term “substantially” indicates that the protective metal coatings 117 and 127 typically cover the lower surfaces 153 and 157 to sufficiently protect the underlying metal from oxidation, moisture, and other environmental conditions to meet packaging application requirements. The protective metal coatings 117 and 127 may also protect the underlying metal during etching, as described and illustrated in FIG. 5. Alternatively, the solder paste may be disposed on both the lower sloped portions 208 a and 308 a and the lower surfaces 153 and 157. The solder paste is then dried or hardened. Alternatively, the solder paste may be reflowed and hardened into a solder bump.

In another embodiment, the protective layers 210 and 310 can include an organic solderability preservative (OSP) layer. The OSP layer may be attached to the lower sloped portions 208 a and 308 a using immersion or rinsing with a solution based on an organic material, or any other suitable process. The organic material may be an imidazole-based material. The OSP layer may be selectively disposed on the lower sloped portions 208 a and 308 a, or alternatively may be disposed on the lower sloped portions 208 a and 308 a, the lower surface 153 of the die pad 101, and the lower surface 157 of at least one lead 171. If the OSP layer is disposed on the lower surfaces 153 and 157, an additional processing operation to remove the OSP layer may be omitted, as the OSP layer typically evaporates at temperatures encountered when soldering the die pad 101 and at least one lead 171 to a PCB.

The use of a solder material and/or an organic material as part of protective layers 210 and 310 is desirable for at least two reasons. First, typical solder materials and organic materials are less costly than metals such as nickel, gold, and tin. Second, solder materials and organic materials can be applied to the die pad 101 and at least one lead 171 without using electrolytic or electroless plating processes, which can simplify the creation of the protective layers 210 and 310.

FIG. 4 illustrates a top view of a portion of a metal carrier plate 400, in accordance with one embodiment of the present invention. The metal carrier plate 400 may be formed as described in FIG. 5. The metal carrier plate 400 includes a base 402, and the base 402 has a central protrusion 404 extending upwardly from the base 402. In this context, the term “central” indicates that the protrusion 404 may be approximately centrally located within the portion of the metal carrier plate 400 shown in FIG. 4. However, the portion of the metal carrier plate 400 shown in FIG. 4 can be variously located within the metal carrier plate 400, including bordering the edge of the metal carrier plate 400. Although the central protrusion 404 is shown as extending completely around a circumference of the base 402 in FIG. 4, the central protrusion 404 may extend partially around the base 402 in another embodiment. A plurality of peripheral protrusions 406 are disposed around the base 402. Although the peripheral protrusions 406 are shown as substantially completely surrounding the base 402 in FIG. 4, the peripheral protrusions 406 may partially surround the base 402 in another embodiment. A corner peripheral protrusion 408 at one of the corners of the portion of the metal carrier plate 400 may be of a different shape and or size from the other peripheral protrusions 406. This corner peripheral protrusion 408 may serve as a recognition mark to facilitate the orientation, during surface mounting, of a resulting package.

The hatched portions of the metal carrier plate 400 (404, 406, and 408) have not been etched, and therefore protrude from the other portions of the metal carrier plate 400 (including part of 402), which have been etched from the top side (see FIG. 5). In one embodiment, the peripheral protrusions 406 are disposed in at least three rows on at least one side of the base 402. After bottom side etching (see FIG. 6), the base 402 and the peripheral protrusions 406 are separated and formed into the die pad 101 and the leads 171, as previously described in FIGS. 1 through 3. Since the peripheral protrusions 406 need not be connected to a disposable portion of a leadframe, as is typically the case for a QFN leadframe, the creation of multiple rows of leads 171 using the processing operations of FIGS. 5 and 6 is significantly more scalable to two or more such rows than is typical QFN processing.

In one embodiment, after bottom side etching (see FIG. 6), the central protrusion 404 may include a ground region to which a chip (e.g., the chip 102) is electrically coupled using bonding wires (e.g., the bonding wires 104). The ground region may completely surround the base 402. Alternatively, the ground region may include one or more ground segments that partially surround the base 402. The central protrusion 404 may also include a power region to which the chip 102 is electrically coupled, and the power region may include one or more power segments. In one embodiment, a ground segment may be a first portion 404 a of the central protrusion 404, and a power segment may be a second portion 404 b of the central protrusion 404. In this case, a first portion of the base 402 connected to the ground segment 404 a can be spaced apart from a second portion of the base 402 connected to the power segment 404 b. The spacing apart may be performed using etching, singulation, or any other suitable process to physically separate the first portion of the base 402 from the second portion of the base 402, such as along the dotted line 410.

It will be understood that the portion of the metal carrier plate 400 shown in FIG. 4 may be alternatively described. For example, the metal carrier plate 400 may include a die receiving area 402 with a peripheral edge region 404. A plurality of peripheral bulges 406 may be disposed around the die receiving area 402. Alternatively, the metal carrier plate 400 may include a protrusion 404 disposed adjacent to the base 402.

FIG. 5 illustrates processing operations for making a metal carrier plate 500, in accordance with one embodiment of the present invention. A first photoresist layer 506 is formed on an upper surface 502 of a copper plate 501, and a second photoresist layer 508 is formed on a lower surface 504 of the copper plate 501. The photoresist layers 506 and 508 are formed by coating, printing, or any other suitable technique. Predetermined or selected portions of the photoresist layers 506 and 508 are photoimaged and developed so as to create first exposed portions 510 and second exposed portions 512 of the copper plate 501. The photoresist layers 506 and 508 may be photochemically defined using a photomask (not shown).

A first metal coating 514 is then formed on the exposed portions 510, and a second metal coating 516 is formed on the exposed portions 512. The metal coatings 514 and 516 can have the same characteristics as previously described for metal coatings 116, 117, 126, and 127. The photoresist layers 506 and 508 are then stripped. Areas 518 of the upper surface 502 of the copper plate 501 without the protection of the metal coating 514 are then etched to form the metal carrier plate 500, including the previously described central region 212 a, central protrusion 213, and peripheral protrusions 406. Alternatively, the etching may form the previously described die receiving area 402 and peripheral bulges 406 as part of the metal carrier plate 500. This etching operation may be referred to as top side etching.

The metal carrier plate 500 typically includes multiple interconnected portions, such as portions 500 a and 500 b. Each portion may include the previously described central region 212 a, central protrusion 213, and peripheral protrusions 406.

FIG. 6 illustrates processing operations for making the semiconductor package 100, in accordance with one embodiment of the present invention. A chip 102 is attached to a central region 212 a (or die receiving area 402) of each portion of a metal carrier plate 500, such as portions 500 a and 500 b. Each chip 102 is attached using an adhesive layer (not shown), as previously described. Each chip 102 is then electrically coupled to peripheral protrusions 406 (or peripheral bulges 406) through bonding wires 104. A package body 108 is then formed over each chip 102 and each of the peripheral protrusions 406. The package body 108 may be composed of a synthetic resin, and may be formed through molding methods such as transfer molding. Areas 620 of the lower surface of the metal carrier plate 500 without the protection of the metal coating 516 are then etched to separate the peripheral protrusions 406 and the central protrusion 213 to form the previously described leads 171 and die pad 101. This etching operation may be referred to as bottom side etching. The leads 171 and the die pad 101 may be formed in each of multiple connected packages sharing package body 108, such as connected packages 600 a and 600 b. Through singulation, the connected packages 600 a and 600 b may be separated into packages 100 a and 100 b. Singulation can be carried out by, for example, sawing, which can create substantially vertical side surfaces of the packages 100 a and 100 b as shown in FIG. 6.

FIG. 7 illustrates processing operations for making a semiconductor package 100 including multiple stacked dies or chips, in accordance with one embodiment of the present invention. A first chip 102 a is attached to a central region 212 a (or die receiving area 402) of each portion of a metal carrier plate 500, such as portions 500 a and 500 b. Each first chip 102 a is attached using an adhesive layer (not shown), as previously described. Each first chip 102 a may then be electrically coupled to at least one portion of a central protrusion 213 (or peripheral edge region 404) through bonding wires 104 a. In another embodiment, each first chip 102 a may be electrically coupled to one or more peripheral protrusions 406.

An attachment layer 700 is then disposed on the upper surface of each first chip 102 a. A second chip 102 b is then coupled to the upper surface of each first chip 102 a by the attachment layer 700. Each second chip 102 b may then be electrically coupled to peripheral protrusions 406 through bonding wires 104 b. In another embodiment, each second chip 102 b may be electrically coupled to at least one portion of the central protrusion 213. Any peripheral protrusion 406 or portion of the central protrusion 213 to which a second chip 102 b is coupled can be electrically isolated from any peripheral protrusion 406 or portion of the central protrusion 213 to which a corresponding first chip 102 a is coupled.

The package body 108 is then formed over each set of stacked chips 102 a and 102 b and each of the peripheral protrusions 406. Areas 620 of the lower surface of the metal carrier plate 500 without the protection of the metal coating 516 are then etched to separate the peripheral protrusions 406 and the central protrusion 213 to form the previously described leads 171 and die pad 101. The leads 171 and the die pad 101 may be formed in each of multiple connected packages sharing package body 108, such as connected packages 600 a and 600 b. Through singulation, the connected packages 600 a and 600 b may be separated into packages 100 a and 100 b.

In one embodiment, the attachment layer 700 includes an adhesive layer. The adhesive layer may be a conductive or a non-conductive adhesive material, such as a non-conductive epoxy. The adhesive layer may be a liquid-type adhesive layer or a film-type adhesive layer, such as a double-sided tape. The adhesive layer may also be a film-on-wire adhesive layer, which has similar characteristics but is typically thicker than the film-type adhesive layer.

In one embodiment, chip 102 b extends beyond the peripheral edge of chip 102 a. One advantage of the film-on-wire adhesive layer is that this adhesive layer can be sufficiently thick so that when chip 102 b is attached to this adhesive layer, there is still sufficient clearance for bonding wires 104 a attached to chip 102 a. If the film-on-wire adhesive layer is not used, then the attachment layer 700 may include a spacer in addition to the liquid-type and/or film-type adhesive layer. The purpose of the spacer is to space apart chips 102 a and 102 b so that there is sufficient clearance for bonding wires 104 a attached to chip 102 a.

As described previously, a resulting package 100 can be made thinner by disposing the chip 102 on the cavity bottom 112 (or upper surface 212 of the base 202). For a package 100 with stacked chips such as in FIG. 7, it may be especially important to take advantage of the additional space provided by the cavity 111 to make the package 100 thinner. In addition, the ordering of stacking may be important. For example, in FIG. 7, the chip 102 b extends beyond the cavity 111 and partly covers over the peripheral edge region 114 of the die pad 101, so the chip 102 b could not be disposed on the cavity bottom 112. However, the chip 102 a is sized so that it can be disposed on the cavity bottom 112. In this case, the chip 102 b may be stacked on top of the chip 102 a if the height of the chip 102 a plus the height of the attachment layer 700 is large enough to provide sufficient clearance above the upper surface 150 of the metal coating 116 disposed on the peripheral edge region 114, and above the bonding wires 104 a.

FIG. 8 illustrates processing operations for making a semiconductor package 100 and surface mounting the semiconductor package 100, in accordance with one embodiment of the present invention. As described previously, leads 171 and die pad 101 may be formed in each of multiple connected packages sharing a package body 108, such as connected packages 600 a and 600 b. In this embodiment, a solder paste 802 is disposed to substantially cover a sloped etched area 308 a of at least one lead 171, and a lower surface 156 of a metal coating 127 disposed on the lower surface 157 of that lead 171. The solder paste 802 is then solidified for defining a solder interface 802 for subsequent surface mounting. Solder paste 800 may also be disposed to substantially cover a sloped etched area 208 a of the die pad 101, and a lower surface 152 of a metal coating 117 of the die pad 101. Through singulation, the connected packages 600 a and 600 b are then separated into packages 100 a and 100 b.

For surface mounting the package 100 a, the solder interfaces 800 and 802 may be reflowed to form liquefied solder masses 804 and 806. The liquefied solder masses 804 and 806 are then placed into contact with a PCB 808 and hardened. The solder interfaces 800 and 802 typically contain enough solder so that upon reflow soldering and surface mounting of the package 100 a, the solder acts as a protective layer for the sloped etched areas 208 a and 308 a by substantially covering these areas.

In addition to the use of the solder as a protective layer, another advantage of the surface mounting process of FIG. 8 is that surface mounting of the package 100 a can be achieved by reflowing the solder interfaces 800 and 802. This removes the need for additional solder paste on the PCB 808 as part of surface mounting of the package 100 a.

FIG. 9 illustrates processing operations for making a semiconductor package 100 and surface mounting the semiconductor package 100, in accordance with another embodiment of the present invention. In this embodiment, the package 100 is provided without solder interfaces 800 and 802 for surface mounting. A sloped etched area 208 a of a die pad 101 and a sloped etched area 308 a of at least one lead 171 may be substantially covered with a protective layer such as an OSP layer, as described previously. Subsequently, solder paste 900 is applied on a PCB 908 in preparation for surface mounting of the package 100. After surface mounting of the package 100, the solder paste is reflowed and then hardened into solder masses 902 attaching the package 100 to the PCB 908.

As described previously, enough solder paste 900 can be applied on the PCB 908 so that upon surface mounting of the package 100 and reflow soldering, the solder acts as a protective layer for the sloped etched areas 208 a and 308 a by substantially covering those areas.

FIG. 10 illustrates a top view of a portion of a metal carrier plate 1000 including a marker bulge 1008 and enlarged peripheral bulges 1010, in accordance with one embodiment of the present invention. The metal carrier plate 1000 may be formed as described in FIG. 5. The metal carrier plate 1000 includes a die receiving area 1002. The die receiving area 1002 may include a peripheral edge region 1004. Although the peripheral edge region 1004 is shown as extending completely around an interior portion of the die receiving area 1002 in FIG. 10, the peripheral edge region 1004 may extend partially around the interior portion of the die receiving area 1002 in another embodiment. The portion of the metal carrier plate 1000 shown in FIG. 10 can be variously located within the metal carrier plate 1000, including bordering the edge of the metal carrier plate 1000. A plurality of peripheral bulges 1006 are disposed in a lead placement area 1001 around the die receiving area 1002. Although the peripheral bulges 1006 and the lead placement area 1001 are shown as substantially completely surrounding the die receiving area 1002 in FIG. 10, the peripheral bulges 1006 and the lead placement area 1001 may partially surround the die receiving area 1002 in another embodiment. The marker bulge 1008 and the enlarged peripheral bulges 1010 may be located in corner regions of the lead placement area 1001 as shown in FIG. 10, or may be located elsewhere in the lead placement area 1001.

The hatched portions of the metal carrier plate 1000 (1004, 1006, 1008, and 1010) have not been etched, and therefore protrude from the other portions of the metal carrier plate 1000 (including part of 1002), which have been etched from the top side (see FIG. 5). As previously described in FIG. 4, the peripheral bulges 1006 are disposed in at least three rows on at least one side of the die receiving area 1002.

FIG. 11 illustrates a cross-sectional view of a semiconductor package 1100, in accordance with the embodiment of FIG. 10. The cross-sectional view corresponds to cross-section A-A shown in FIG. 10 after bottom side etching (see FIG. 6). The die receiving area 1002, the peripheral bulges 1006, the marker bulge 1008, and the enlarged peripheral bulges 1010 are separated and formed into the die pad 101, the leads 171, a marker lead 1108, and enlarged leads 1110. The die pad 101 and the leads 171 are as previously described in FIGS. 1 through 3. The marker lead 1108 and the enlarged leads 1110 have characteristics similar to those of the leads 171, except that the marker lead 1108 and the enlarged leads 1110 may be of a different shape and/or size from the other leads 171. In addition, the marker lead 1108 may be of a different shape and/or size from the enlarged leads 1110. Because the marker lead 1108 has a different size and/or shape from the enlarged leads 1110 and the rest of the leads 171, the marker lead 1108 may serve as a recognition mark to facilitate the orientation, during surface mounting, of the resulting package. Alternatively, the leads 1108 and 1110 may be similarly configured, and the semiconductor package 1100 may include a separate recognition mark, such as a mark formed in the package body 108 or the die pad 101. The other characteristics of the semiconductor package 1100 are as previously described for the semiconductor package 100 in FIGS. 1 through 3. It will be understood that multiple chips 102 may be stacked within the semiconductor package 1100 as previously described in FIG. 7.

In one embodiment, a surface area of a lower surface 1118 of the marker lead 1108 may be at least fifty percent greater than an average of surface areas of a lower surface 157 of the other leads 171, such as at least 1.5 times, 2 times, or 3 times larger. Also, an average of surface areas of lower surfaces 1120 of the enlarged leads 1110 may be at least fifty percent greater than the average of surface areas of the lower surface 157 of the other leads 171, such as at least 1.5 times, 2 times, or 3 times larger. The marker lead 1108 and the enlarged leads 1110 may be located in the corner regions of the lead placement area 1001, as shown in FIG. 10. During surface mounting, the enlarged surface areas of the lower surfaces 1118 and/or 1120 provide additional area for solder to attach the enlarged leads 1110 and/or the marker lead 1108 to a PCB. This can strengthen the solder connections near the corners of the semiconductor package 1100, where stress can be greatest due to differential thermal expansion between the package body 108 and the leads 1108 and 1110. This may reduce the likelihood of cracking of these solder connections, and thus increase the reliability of surface mounting.

In one embodiment, the lower surface 1118 of the marker lead 1108 may have a substantially circular shape, while the lower surfaces 1120 of each of the enlarged leads 1110 may have a substantially square shape. Alternatively, the lower surface 1118 of the marker lead 1108 may have a substantially square shape, while the lower surfaces 1120 of each of the enlarged leads 1110 may have a substantially circular shape. In this context, the term “substantially” is used to indicate that the lower surfaces 1118 and 1120 need not be perfectly square or circular. For example, the lower surfaces 1120 of each of the enlarged leads 1110 may be mostly square but may have a rounded corner rather than a sharp corner. The lower surfaces 1118 and 1120 may also include surface non-uniformities or roughness in the form of small peaks, such as asperities, that may point outwards from the center of the leads 1108 and 1110, respectively.

It will be understood that the portion of the metal carrier plate 1000 shown in FIG. 10 may be alternatively described. For example, the metal carrier plate 1000 may include a base 1002 with a protrusion 1004 disposed adjacent to the base 1002. The protrusion 1004 may also be described as a central protrusion 1004. A plurality of peripheral protrusions 1006, a marker protrusion 1008, and enlarged protrusions 1010 may be disposed around the base 1002.

FIG. 12 illustrates a top view of a portion of a metal carrier plate 1200 including a die receiving area 1202 including a peripheral edge region 1204, in accordance with one embodiment of the present invention. Certain aspects of the metal carrier plate 1200 may be implemented similarly to embodiments previously described herein, such as in FIGS. 4 and 10. Certain aspects of the metal carrier plate 1200 may also be formed as previously described herein, such as in FIG. 5. In this embodiment, the peripheral edge region 1204 is segmented so that the peripheral edge region 1204 extends partially around an interior portion of the die receiving area 1202. The peripheral edge region 1204 may include one or more segmented peripheral edge regions, illustrated as segmented peripheral edge regions 1204A-1204E.

The hatched portions of the top view of the metal carrier plate 1200 (the segmented peripheral edge regions 1204A-1204E, the peripheral bulges 1206, the marker bulge 1208, and the enlarged peripheral bulges 1210) have not been etched, and therefore protrude from the other portions of the metal carrier plate 1200 (including part of the die receiving area 1202), which have been etched from the top side, as previously described in FIG. 5. In this embodiment, the top side etching includes etching that removes portions of the metal carrier plate 1200 to separate upper portions of the segmented peripheral edge regions 1204A-1204E.

FIG. 13 illustrates a bottom view of the portion of the metal carrier plate 1200 of FIG. 12, in accordance with one embodiment of the present invention. The hatched portions of the bottom view of the metal carrier plate 1200 show areas of the lower surface of the metal carrier plate 1200 that are covered by the metal coating 516, as previously described in FIG. 5. The metal coating 516 protects the die receiving area 1202, the segmented peripheral edge regions 1204A-1204E, the peripheral bulges 1206, the marker bulge 1208, and the enlarged peripheral bulges 1210 from bottom side etching, as previously described in FIG. 6.

FIG. 14 illustrates processing operations for making a semiconductor package 1400 including a ground region 1470, in accordance with one embodiment of the present invention. Certain aspects of the semiconductor package 1400 may be made similarly to embodiments previously described herein, such as in FIGS. 5 and 6. Certain aspects of the semiconductor package 1400 may also be implemented similarly to embodiments previously described herein, such as in FIGS. 1-3 and 11. A chip 102 is attached to a die receiving area 1402 of portions 1475 a and 1475 b of a metal carrier plate 1499. The chip 102 is then electrically coupled to peripheral bulges 1406 and a segmented peripheral edge region 1404. The metal coating 1416 covers areas corresponding to those covered by the metal coating 516 in FIG. 13, including portions of the lower surface of the die receiving area 1402. These covered portions of the lower surface of the die receiving area 1402 include the lower surface of the segmented peripheral edge region 1404. However, the metal coating 1416 does not cover unprotected areas 1420 of the lower surface of the metal carrier plate 1499. The unprotected areas 1420 include areas of the metal carrier plate 1499 that connect lower portions of the segmented peripheral edge region 1404 to other segmented peripheral edge regions.

The unprotected areas 1420 are then etched to separate the die receiving area 1402 (including the segmented peripheral edge region 1404) and the peripheral bulges 1406 to form the die pad 1401 and the previously described leads 171. This etching operation may be referred to as bottom side etching, as previously described. Certain aspects of the die pad 1401 may be implemented similarly to embodiments previously described herein, such as die pad 101 in FIGS. 1-3. The die pad 1401 may include the previously described base 202 and protrusion 213, where the protrusion 213 may be disposed adjacent to the base 202. The protrusion 213 may include the ground region 1470, to which the chip 102 is electrically coupled using bonding wires 104. The ground region 1470 may include one or more ground segments that partially surround the base 202. For example, a ground segment 1470A may be adjacent to a first side of the base 202, and another ground segment (not shown) may be adjacent to a second side of the base 202.

In one embodiment, an upper surface 1471 of the ground segment 1470A is included in the upper surface 151 of the protrusion 213. In one embodiment, substantially the entire upper surface 1471 is a metallic conductor and corresponds to a ground connection area for the bonding wires 104 electrically coupled to the chip 102.

Spacing 1496 refers to the distance between the centers of ground region 1470 and adjacent lead 171. For certain implementations, the spacing 1496 is between about 0.35 millimeters and about 0.55 millimeters, although the spacing 1496 is not constrained to this range. The spacing 1496 can be controlled by etching, such as through a top side etching process, as previously described in FIG. 5.

In one embodiment, a lower surface 1472 of the ground segment 1470A corresponds to the lower surface 253 of the protrusion 213, as the entire lower surface 253 is electrically coupled to ground. A surface area of the lower surface 1472 may be at least three times larger than an average of surface areas of lower surfaces 157 of leads 171, such as at least 3 times, 5 times, 10 times, or 20 times larger.

In one embodiment, a surface area of the upper surface 151 of the protrusion 213 may be at least three times larger than an average of surface areas of lower surfaces 157 of leads 171, such as at least 3 times, 5 times, 10 times, or 20 times larger.

The leads 171 and the die pad 101 may be formed in each of multiple connected packages sharing package body 108, such as connected packages 1480 a and 1480 b. Through singulation, the connected packages 1480 a and 1480 b may be separated into packages 1400 a and 1400 b, as previously described in FIG. 6. It will be understood that multiple chips 102 may be stacked within the semiconductor package 1400 as previously described in FIG. 7.

One advantage of ground segments over a ground ring that extends completely around a chip is that ground segments, which extend partially around the chip, take up less space in a package than the ground ring. It may then be possible, for example, to reduce the size of the package and/or to utilize the space saved to increase the number of leads in the package.

FIG. 15 illustrates a top view of a portion of a metal carrier plate 1500 including enlarged peripheral bulges 1505 and a die receiving area 1502 including a peripheral edge region 1504, in accordance with one embodiment of the present invention. Certain aspects of the metal carrier plate 1500 may be implemented similarly to embodiments previously described herein, such as in FIGS. 4, 10, and 12. Certain aspects of the metal carrier plate 1500 may also be formed as previously described herein, such as in FIG. 5. In this embodiment, the peripheral edge region 1504 extends completely around an interior portion of the die receiving area 1502.

The hatched portions of the top view of the metal carrier plate 1500 (the peripheral edge region 1504, the enlarged peripheral bulges 1505, the peripheral bulges 1506, the marker bulge 1508, and the enlarged peripheral bulges 1510) have not been etched, and therefore protrude from the other portions of the metal carrier plate 1500 (including part of the die receiving area 1502), which have been etched from the top side, as previously described in FIG. 5.

FIG. 16 illustrates a bottom view of the portion of the metal carrier plate 1500 of FIG. 15, in accordance with one embodiment of the present invention. The hatched portions of the bottom view of the metal carrier plate 1500 show areas of the lower surface of the metal carrier plate 1500 that are covered by the metal coating 516, as previously described in FIG. 5. The metal coating 516 protects the die receiving area 1502, the peripheral edge region 1504, the enlarged peripheral bulges 1505, the peripheral bulges 1506, the marker bulge 1508, and the enlarged peripheral bulges 1510 from bottom side etching, as previously described in FIG. 6.

FIG. 17 illustrates processing operations for making a semiconductor package 1700 including a ground region 1770 and a power region 1790, in accordance with one embodiment of the present invention. Certain aspects of the semiconductor package 1700 may be made similarly to embodiments previously described herein, such as in FIGS. 5, 6, and 14. Certain aspects of the semiconductor package 1700 may also be implemented similarly to embodiments previously described herein, such as in FIGS. 1-3, 11, and 14. A chip 102 is attached to a die receiving area 1702 of portions 1775 a and 1775 b of a metal carrier plate 1799. The chip 102 is then electrically coupled to enlarged peripheral bulge 1705, peripheral bulges 1706, and peripheral edge region 1704. The metal coating 1716 covers areas corresponding to those covered by the metal coating 516 in FIG. 16, and does not cover unprotected areas 1720.

The unprotected areas 1720 are then etched to separate the die receiving area 1702 (including the peripheral edge region 1704), the enlarged peripheral bulge 1705, and the peripheral bulges 1706 to form die pad 1701, the power region 1790, and the previously described leads 171. This etching operation may be referred to as bottom side etching, as previously described. Certain aspects of the die pad 1701 may be implemented similarly to embodiments previously described herein, such as die pad 101 in FIGS. 1-3. The die pad 1701 may include the previously described base 202 and protrusion 213, where the protrusion 213 may be disposed adjacent to the base 202. The protrusion 213 may include a ground region 1770, to which the chip 102 is electrically coupled using bonding wires 104.

In one embodiment, the ground region 1770 completely surrounds the base 202. The power region 1790 may include one or more power segments that partially surround the base 202 and the ground region 1770. For example, a power segment 1790A may be adjacent to a first side of the ground region 1770, and another power segment (not shown) may be adjacent to a second side of the ground region 1770. Spacing 1794 refers to the distance between the centers of ground region 1770 and the power region 1790, if adjacent to the ground region 1770. Spacing 1796 refers to the distance between the centers of ground region 1770 and adjacent lead 171. For certain implementations, each of the spacings 1794 and 1796 is between about 0.35 millimeters and about 0.55 millimeters, although the spacings 1794 and 1796 are not constrained to this range. The spacings 1794 and 1796 may be substantially equal. In this context, the term “substantially” indicates, in part, that the spacings 1794 and 1796 are equal within a tolerance of a process used to control the spacings 1794 and 1796. The spacings 1794 and 1796 can be controlled by etching, such as through a top side etching process, as previously described in FIG. 5.

In one embodiment, substantially the entire upper surface 1771 of the ground region 1770 is a metallic conductor and corresponds to a ground connection area for the bonding wires 104 electrically coupled to the chip 102. The ground connection area may correspond to a ground ring. Similarly, in one embodiment, substantially the entire upper surface 1791 of the power region 1790 is a metallic conductor and corresponds to a power connection area for the bonding wires 104 electrically coupled to the chip 102. In one embodiment, a surface area of the lower surface 1792 of the power region 1790 may be at least three times larger than an average of surface areas of lower surfaces 157 of leads 171, such as at least 3 times, 5 times, 10 times, or 20 times larger.

In one embodiment, the ground region 1770 and the power region 1790 may be electrically isolated from each other. Alternatively, the ground region 1770 and the power region 1790 may be electrically coupled by a surface mountable device 1798. The surface mountable device 1798 may be a decoupling capacitor used to suppress power supply noise. The surface mountable device 1798 may be connected to the ground region 1770 and the power region 1790 prior to the forming of the package body 108 over the metal carrier plate 1799, as previously described in FIG. 6.

The leads 171 and the die pad 1701 may be formed in each of multiple connected packages sharing package body 108, such as connected packages 1780 a and 1780 b. Through singulation, the connected packages 1780 a and 1780 b may be separated into packages 1700 a and 1700 b, as previously described in FIG. 6. It will be understood that multiple chips 102 may be stacked within the semiconductor package 1700 as previously described in FIG. 7.

One advantage of using a power segment for multiple power connections is that a power segment can enable the same number of power connections as multiple adjacent leads while taking up less space in the package. If multiple leads 171 are used for power connections instead of a power segment, a lead spacing 145 (previously described in FIGS. 1-3) between the multiple leads 171 is unusable for additional leads 171. In addition, one advantage of power segments over a power ring that extends completely around a chip is that power segments, which only extend partially around the chip, take up less space in a package than the power ring. It may then be possible, for example, to reduce the size of the package and/or to utilize the space saved to increase the number of leads in the package.

FIG. 18 illustrates a top view of a portion of a metal carrier plate 1800 including parts of a die receiving area 1802 including multiple parts 1802A-1802C, in accordance with one embodiment of the present invention. Certain aspects of the metal carrier plate 1800 may be implemented similarly to embodiments previously described herein, such as in FIGS. 4, 10, 12, and 15. Certain aspects of the metal carrier plate 1800 may also be formed as previously described herein, such as in FIG. 5. The dotted lines 1820, 1821, and 1822 show the boundaries of the multiple parts 1802A-1802C of the die receiving area 1802. The multiple parts 1802A-1802C are separated by bottom side etching, as previously described in FIG. 6. In this embodiment, the peripheral edge region 1804 is segmented so that the peripheral edge region 1804 extends partially around an interior portion of the die receiving area 1802. The peripheral edge region 1804 may include one or more segmented peripheral edge regions, illustrated in this embodiment as segmented peripheral edge regions 1804A-1804C.

The hatched portions of the top view of the metal carrier plate 1800 (the peripheral edge region 1804, the peripheral bulges 1806, the marker bulge 1808, and the enlarged peripheral bulges 1810) have not been etched, and therefore protrude from the other portions of the metal carrier plate 1800 (including part of the die receiving area 1802), which have been etched from the top side, as previously described in FIG. 5.

Alternatively, the peripheral edge region 1804 of the die receiving area 1802 may be substantially coplanar with the die receiving area 1802. In this context, the term “substantially” indicates, in part, that the peripheral edge region 1804 is coplanar with the die receiving area within a tolerance of a process used to create the die receiving area 1802 and the peripheral edge region 1804. The degree to which the die receiving area 1802 and the peripheral edge region 1804 are coplanar can be controlled by etching, such as through a top side etching process, as previously described in FIG. 5.

FIG. 19 illustrates a bottom view of the portion of the metal carrier plate 1800 of FIG. 18, in accordance with one embodiment of the present invention. The hatched portions of the bottom view of the metal carrier plate 1800 show areas of the lower surface of the metal carrier plate 1800 that are covered by the metal coating 516, as previously described in FIG. 5. The metal coating 516 protects the die receiving area 1802, the peripheral edge region 1804, the peripheral bulges 1806, the marker bulge 1808, and the enlarged peripheral bulges 1810 from bottom side etching, as previously described in FIG. 6.

FIG. 20 illustrates processing operations for making a semiconductor package 2000 including a die pad 2001 with separated parts 2001A and 2001B, in accordance with one embodiment of the present invention. Certain aspects of the semiconductor package 2000 may be made similarly to embodiments previously described herein, such as in FIGS. 5, 6, 14, and 17. Certain aspects of the semiconductor package 2000 may also be implemented similarly to embodiments previously described herein, such as in FIGS. 1-3, 11, 14, and 17. A chip 102 is attached to a die receiving area 2002 of portions 2075 a and 2075 b of a metal carrier plate 2099. The die receiving area 2002 has first parts 2002A and second part 2002B that have boundaries as previously described in FIG. 18. The first part 2002A may include a segmented peripheral edge region 2004A, and the second part 2002B may include a segmented peripheral edge region 2004B. The chip 102 is then electrically coupled to the segmented peripheral edge region 2004A, the segmented peripheral edge region 2004B, and peripheral bulges 2006. The metal coating 2016 covers areas corresponding to those covered by the metal coating 516 in FIG. 19, including portions of the lower surface of the die receiving area 2002. These covered portions of the lower surface of the die receiving area 2002 include the lower surfaces of the segmented peripheral edge regions 2004A and 2004B. However, the metal coating 2016 does not cover unprotected areas 2020 of the lower surface of the metal carrier plate 2099. The unprotected areas 2020 include areas of the metal carrier plate 2099 that connect the first part 2002A of the die receiving area 2002 to the second part 2002B.

The unprotected areas 2020 are then etched to separate the first part 2002A, the second part 20023, and the peripheral bulges 2006 to form the first part 2001A of the die pad 2001, the second part 2001B of the die pad 2001, and the previously described leads 171. This etching operation may be referred to as bottom side etching, as previously described. In one embodiment, the lower surfaces of each of the first part 2001A and the second part 2001B have substantially polygonal shapes. A polygonal shape may include at least three vertices. Polygonal shapes include but are not limited to triangles, squares, and rectangles. The first part 2001A and the second part 2001B may have different shapes. In this context, the term “substantially” is used to indicate that the lower surfaces of each of the first part 2001A and the second part 2001B need not be perfectly polygonal. For example, the lower surfaces of each of the first part 2001A and the second part 2001B may include surface non-uniformities or roughness in the form of small peaks, such as asperities, that may point outwards from the center of the first part 2001A and the second part 2001B, respectively.

Certain aspects of the die pad 2001 may be implemented similarly to embodiments previously described herein, such as die pad 101 in FIGS. 1-3. Each part of the die pad 2001 may include the previously described base 202 and protrusion 213, where the protrusion 213 may be disposed adjacent to the base 202. In one embodiment, the protrusion 213A of the first part 2001A may include a ground region 2070, to which the chip 102 is electrically coupled using bonding wires 104. The ground region 2070 extends partially around the base 202A. The protrusion 213B of the second part 2001B may include a power region 2090, to which the chip 102 is electrically coupled using bonding wires 104. The power region 2090 extends partially around the base 202B.

Distance 2095 refers to the distance separating the first part 2001A from the second part 2001B. For certain implementations, the distance 2095 is between about 0.1 and about 0.3 millimeters, although the distance 2095 is not constrained to this range. The distance 2095 can be controlled by etching, such as through a top side etching process, as previously described in FIG. 5.

In one embodiment, a surface area of a lower surface 2072 of the ground region 2070 may be at least three times larger than an average of surface areas of the lower surfaces 157 of leads 171, such as at least 3 times, 5 times, 10 times, or 20 times larger. Similarly, a surface area of the lower surface 2092 of the power region 2090 may be at least three times larger than an average of surface areas of the lower surfaces 157 of leads 171, such as at least 3 times, 5 times, 10 times, or 20 times larger.

In one embodiment, a surface area of a lower surface 2011 of the first part 2001A may be at least three times larger than an average of surface areas of the lower surfaces 157 of leads 171, such as at least 3 times, 5 times, 10 times, or 20 times larger. Similarly, a surface area of a lower surface 2012 of the second part 2001B may be at least three times larger than an average of surface areas of the lower surfaces 157 of leads 171, such as at least 3 times, 5 times, 10 times, or 20 times larger.

In one embodiment, the ground region 2070 and the power region 2090 may be electrically isolated from each other. Alternatively, the ground region 2070 and the power region 2090 may be electrically coupled by a surface mountable device 2098, as previously described in FIG. 17.

The leads 171 and the die pad 2001 may be formed in each of multiple connected packages sharing package body 108, such as connected packages 2080 a and 2080 b. Through singulation, the connected packages 2080 a and 2080 b may be separated into packages 2000 a and 2000 b, as previously described in FIG. 6. It will be understood that multiple chips 102 may be stacked within the semiconductor package 2000 as previously described in FIG. 7.

One advantage of separating a die pad into at least a first part that serves as a ground region and a second part that serves as a power region is that both ground and power connections are made available to a chip in approximately the same amount of space needed for a around ring. It may then be possible, for example, to reduce the size of the package and/or to utilize the space saved to increase the number of leads in the package. In addition, the die pad can be separated into multiple parts that serve as ground regions and/or multiple parts that serve as power regions to enhance electrical performance for certain package designs.

It will be understood that the metal carrier plates shown in FIGS. 12-20 may be alternatively described. For example, the metal carrier plate 1200 of FIG. 12 may include a base 1202 with a protrusion 1204 disposed adjacent to the base 1202. The protrusion 1204 may also be described as a central protrusion 1204. A plurality of peripheral protrusions 1206, a marker protrusion 1208, and enlarged protrusions 1210 may be disposed around the base 1202.

While the methods disclosed herein have been described with reference to particular operations performed in a particular order, it will be understood that these operations may be combined, sub-divided, or re-ordered to form an equivalent method without departing from the teachings of the invention. Accordingly, unless specifically indicated herein, the order and grouping of the operations are not limitations of the invention.

The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that specific details are not required in order to practice the invention. Thus, the foregoing descriptions of specific embodiments of the invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed; many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, they thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the following claims and their equivalents define the scope of the invention. 

1. A semiconductor package comprising: a die pad including: a first part that includes: a first peripheral edge region comprising a ground region; and a lower surface; a second part that is spaced apart from the first part and that includes: a second peripheral edge region comprising a power region; and a lower surface; a plurality of leads disposed around the die pad; a first semiconductor chip disposed on the die pad and electrically coupled to the ground region, the power region, and the plurality of leads; and a package body formed over the first semiconductor chip and the plurality of leads.
 2. The semiconductor package of claim 1, wherein the lower surfaces of each of the first part and the second part have substantially polygonal shapes.
 3. The semiconductor package of claim 1, wherein: each of the plurality of leads includes a lower surface having a first surface area; the ground region is a ground segment; and a second surface area of the lower surface of the first part is at least three times greater than an average of the first surface areas of the plurality of leads.
 4. The semiconductor package of claim 1, wherein: each of the plurality of leads includes a lower surface having a first surface area; the power region is a power segment; and a second surface area of the lower surface of the second part is at least three times greater than an average of the first surface areas of the plurality of leads.
 5. The semiconductor package of claim 1, wherein the first part and the second part are physically separated by a distance of between 0.1 millimeters and 0.3 millimeters.
 6. The semiconductor package of claim 1, wherein the package body substantially covers the die pad and the plurality of leads except for at least the lower surfaces of the first part, the second part, and the plurality of leads.
 7. The semiconductor package of claim 1, wherein each part of the die pad further includes: an upper surface; an upper sloped portion disposed adjacent to the upper surface of the first part and the second part; and a lower sloped portion disposed adjacent to the lower surface of the first part and the second part; wherein the package body substantially covers the upper sloped portions of the first part and the second part, and the lower sloped portions of the first part and the second part at least partially extend outwardly from a lower surface of the package body.
 8. The semiconductor package of claim 7, wherein a standoff distance by which at least one part of the die pad extends outwardly from the lower surface of the package body is between twenty percent and fifty percent of a thickness of the at least one part.
 9. The semiconductor package of claim 7, wherein each of the plurality of leads further includes: an upper surface; an upper sloped portion disposed adjacent to the upper surface of the each of the plurality of leads; and a lower sloped portion disposed adjacent to the lower surface of the each of the plurality of leads; wherein the package body substantially covers the upper sloped portions of the plurality of leads, and the lower sloped portions of the plurality of leads at least partially extend outwardly from the lower surface of the package body.
 10. The semiconductor package of claim 1, wherein: the first peripheral edge region and the second peripheral edge region at least partially define a cavity with a cavity bottom; and the package body substantially fills the cavity.
 11. The semiconductor package of claim 1, further comprising an attachment layer and a second semiconductor chip coupled to an upper surface of the first semiconductor chip by the attachment layer, wherein the package body is formed over the second semiconductor chip, and wherein the attachment layer includes an adhesive layer.
 12. A semiconductor package comprising: a die pad including: a base including an upper surface and a lower surface; a protrusion disposed adjacent to the base, wherein the protrusion includes: an upper surface; and a lower surface; wherein at least a portion of the protrusion is a ground region; and a first side surface extending between the upper surface of the protrusion and the lower surface of the protrusion, the first side surface including a first peak; a plurality of leads disposed around the die pad, each including a lower surface with a first surface area, and at least one of the plurality of leads including a second side surface including a second peak; a first power segment disposed adjacent to the protrusion and including a lower surface with a second surface area that is at least three times greater than an average of the first surface areas of the plurality of leads; a semiconductor chip disposed on the upper surface of the base and electrically coupled to the ground region, the first power segment, and the plurality of leads; and a package body formed over the semiconductor chip and the plurality of leads so that the package body substantially covers the upper surface of the base, at least a portion of the first side surface above the first peak, and at least a portion of the second side surface above the second peak, and so that at least a portion of the first side surface below the first peak and at least a portion of the second side surface below the second peak protrude from a lower surface of the package body.
 13. The semiconductor package of claim 12, wherein the ground region surrounds the base.
 14. The semiconductor package of claim 13, wherein the upper surface of the protrusion includes a ground connection area that is a ground ring.
 15. The semiconductor package of claim 13, further comprising a second power segment, wherein: the first power segment is adjacent to a first side of the ground region; and the second power segment is adjacent to a second side of the ground region.
 16. The semiconductor package of claim 12, wherein a first spacing of at least one of the plurality of leads and the ground region is substantially equal to a second spacing of the first power segment and the ground region.
 17. The semiconductor package of claim 12, wherein: the ground region is a ground segment; and a third surface area of the upper surface of the protrusion is at least three times greater than the average of the first surface areas of the plurality of leads.
 18. A semiconductor package comprising: a die pad including: a base including an upper surface and a lower surface; a protrusion disposed adjacent to the base, wherein the protrusion includes: an upper surface; and a lower surface with a first surface area; wherein at least a portion of the protrusion is a ground segment; and a first side surface extending between the upper surface of the protrusion and the lower surface of the protrusion, the first side surface including a first peak; a plurality of leads disposed around the die pad, each including a lower surface with a second surface area, and at least one of the plurality of leads including a second side surface including a second peak, wherein the first surface area is at least three times greater than an average of the second surface areas of the plurality of leads; a semiconductor chip disposed on the upper surface of the base and electrically coupled to the ground segment and the plurality of leads; and a package body formed over the semiconductor chip and the plurality of leads so that the package body substantially covers the upper surface of the base, at least a portion of the first side surface above the first peak, and at least a portion of the second side surface above the second peak, and so that at least a portion of the first side surface below the first peak and at least a portion of the second side surface below the second peak protrude from a lower surface of the package body.
 19. The semiconductor package of claim 18, wherein a standoff distance by which the portion of the first side surface below the first peak and the portion of the second side surface below the second peak protrude from the lower surface of the package body is between 0.025 millimeters and 0.0625 millimeters.
 20. The semiconductor package of claim 18, further comprising a marker lead disposed around the die pad, wherein a lower surface of the marker lead has a different shape from the lower surfaces of the plurality of leads.
 21. A method of making a semiconductor package comprising: providing a metal carrier plate including (1) a lower surface, (2) an upper surface including a die receiving area, (3) a plurality of peripheral bulges, each being disposed around the die receiving area and having an upper surface, (4) a first metal coating formed on the upper surfaces of the plurality of peripheral bulges, and (5) a second metal coating formed on the lower surface of the metal carrier plate below the plurality of peripheral bulges, a first part of the die receiving area, and a second part of the die receiving area; attaching a first semiconductor chip to the die receiving area; electrically coupling the first semiconductor chip to the plurality of peripheral bulges; forming a package body over the first semiconductor chip and the plurality of peripheral bulges; and etching areas on the lower surface of the metal carrier plate without the second metal coating formed thereon such that (1) the plurality of peripheral bulges, the first part of the die receiving area, and the second part of the die receiving area are separated from one another so as to form a plurality of leads, a first part of a die pad, and a second part of the die pad that is spaced apart from the first part, (2) each of the plurality of leads includes a sloped etched area disposed adjacent to a lower surface of the each of the plurality of leads, (3) each part of the die pad includes a sloped etched area disposed adjacent to a lower surface of the each part, and (4) the sloped etched areas of the first part and the second part of the die pad and of the plurality of leads at least partially extend outwardly from a lower surface of the package body.
 22. The method of claim 21, wherein: the first part of the die pad includes a ground region; and the second part of the die pad includes a power region.
 23. The method of claim 21, wherein the first part of the die pad and the second part of the die pad are separated by a distance of between 0.1 millimeters and 0.3 millimeters.
 24. The method of claim 21, wherein a standoff distance by which at least one of the plurality of leads extends outwardly from the lower surface of the package body is between twenty percent and fifty percent of a thickness of the at least one of the plurality of leads.
 25. The method of claim 21, further comprising: attaching a second semiconductor chip to an upper surface of the first semiconductor chip by an attachment layer, wherein the second semiconductor chip extends beyond a peripheral edge of the first semiconductor chip; wherein the package body is formed over the second semiconductor chip.
 26. The method of claim 21, wherein the metal carrier plate is formed by: providing a copper plate having an upper surface and a lower surface; applying a first photoresist layer on the upper surface of the copper plate and a second photoresist layer on the lower surface of the copper plate; photoimaging and developing predetermined portions of the first photoresist layer and the second photoresist layer so as to create first exposed portions of the upper surface of the copper plate and second exposed portions of the lower surface of the copper plate; forming the first metal coating on the first exposed portions and the second metal coating on the second exposed portions; stripping the first photoresist layer; etching areas on the upper surface of the copper plate without the first metal coating formed thereon so as to form the die receiving area and the plurality of peripheral bulges; and stripping the second photoresist layer. 